SNPP CrIS Sensor Data Records (SDRs) – Change of spectral resolution

SNPP CrIS SDRs will switch to Full Spectral Resolution on 22 April 2020.

Thursday, 27 February 2020

The SNPP CrIS SDRs from NOAA that we currently distribute are in nominal spectral resolution (NSR) mode, as follows:

  • The global data distributed on EUMETCast consist of 1305 spectral channels.
  • The global data distributed on the GTS consist of a reduced set of 399 spectral channels.
  • The regional EARS data distributed on both EUMETCast and the GTS consist of the same reduced set of 399 spectral channels.

NOAA plans to terminate the NSR mode on 4 May 2020.

In anticipation of this, from 22 April 2020, we plan to start distributing SNPP CrIS SDRs at full spectral resolution (FSR) mode for global and regional services. This means the following:

  • The number of spectral channels will increase from 1305 to 2211 for the global data distributed on EUMETCast.
  • For the global data distributed on the GTS and for the regional data, the number and position of channels will change, according to the definition by the ITWG (International TOVS Working Group). The number of channels will increase from 399 to 431.

This will bring the SNPP CrIS data in line with the corresponding NOAA-20 data which are already distributed in FSR mode. On the same date, 22 April 2020, the distribution of SNPP CrIS SDRs in NSR will be stopped.

More details on the CrIS FSR mode

The change to FSR mode will also involve an increase in data volumes:

  • For the global data distributed on EUMETCast: 60% increase, resulting in a total of ~12.8 Gb/day.
  • For the global data distributed on the GTS and the regional data: 10% increase, resulting in a total of ~0,67 Gb/day.

Despite the increase of spectral channels, the FSR data may cover a smaller range of GTS bulletin headers for the global data. The data volume per bulletin will increase, respectively.

The GTS bulletin headers will change as follows:

  • For the global data: INCX[01-30]EUMP
  • For the regional data: INCX[01-09]EUMS

Note: The EUMETCast channels on which SNPP CrIS global and regional data are distributed will change on 15 April — see related news: Change of EUMETCast channels for SNPP CrIS and ATMS data

Sample SNPP CrIS FSR data are available on our FTP server:

You will find three folders with the following files:

  • Global data for EUMETCast
  • Global data for the GTS
  • Regional EARS data

For more information, contact our User Service Helpdesk.

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